Commit graph

94 commits

Author SHA1 Message Date
Heiko Carstens
12d8471315 s390/uaccess: add "fallthrough" comments
Add "fallthrough" comments so nobody wonders if a break statement is missing.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-05-02 15:50:19 +02:00
Stephen Boyd
446f24d119 Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
The help text for this config is duplicated across the x86, parisc, and
s390 Kconfig.debug files.  Arnd Bergman noted that the help text was
slightly misleading and should be fixed to state that enabling this
option isn't a problem when using pre 4.4 gcc.

To simplify the rewording, consolidate the text into lib/Kconfig.debug
and modify it there to be more explicit about when you should say N to
this config.

Also, make the text a bit more generic by stating that this option
enables compile time checks so we can cover architectures which emit
warnings vs.  ones which emit errors.  The details of how an
architecture decided to implement the checks isn't as important as the
concept of compile time checking of copy_from_user() calls.

While we're doing this, remove all the copy_from_user_overflow() code
that's duplicated many times and place it into lib/ so that any
architecture supporting this option can get the function for free.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-30 17:04:09 -07:00
Heiko Carstens
ea81531de2 s390/uaccess: fix page table walk
When translating user space addresses to kernel addresses the follow_table()
function had two bugs:

- PROT_NONE mappings could be read accessed via the kernel mapping. That is
  e.g. putting a filename into a user page, then protecting the page with
  PROT_NONE and afterwards issuing the "open" syscall with a pointer to
  the filename would incorrectly succeed.

- when walking the page tables it used the pgd/pud/pmd/pte primitives which
  with dynamic page tables give no indication which real level of page tables
  is being walked (region2, region3, segment or page table). So in case of an
  exception the translation exception code passed to __handle_fault() is not
  necessarily correct.
  This is not really an issue since __handle_fault() doesn't evaluate the code.
  Only in case of e.g. a SIGBUS this code gets passed to user space. If user
  space can do something sane with the value is a different question though.

To fix these issues don't use any Linux primitives. Only walk the page tables
like the hardware would do it, however we leave quite some checks away since
we know that we only have full size page tables and each index is within bounds.

In theory this should fix all issues...

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-04-02 08:53:08 +02:00
Heiko Carstens
b7fef2dd72 s390/uaccess: fix clear_user_pt()
The page table walker variant of clear_user() is supposed to copy the
contents of the empty zero page to user space.
However since 238ec4ef "[S390] zero page cache synonyms" empty_zero_page
is not anymore the page itself but contains the pointer to the empty zero
pages. Therefore the page table walker variant of clear_user() copied
the address of the first empty zero page and afterwards more or less
random data to user space instead of clearing the given user space range.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-03-21 13:35:38 +01:00
Heiko Carstens
066c437359 s390/uaccess: fix kernel ds access for page table walk
When the kernel resides in home space and the mvcos instruction is not
available uaccesses for kernel ds happen via simple strnlen() or memcpy()
calls.
This however can break badly, since uaccesses in kernel space may fail as
well, especially if CONFIG_DEBUG_PAGEALLOC is turned on.

To fix this implement strnlen_kernel() and copy_in_kernel() functions
which can only be used by the page table uaccess functions. These two
functions detect invalid memory accesses and return the correct length
of processed data.. Both functions are more or less a copy of the std
variants without sacf calls.

Fixes ipl crashes on 31 bit machines as well on 64 bit machines without
mvcos. Caused by changing the default address space of the kernel being
home space.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-28 09:37:12 +01:00
Heiko Carstens
225cf8d69c s390/uaccess: fix strncpy_from_user string length check
The "standard" and page table walk variants of strncpy_from_user() first
check the length of the to be copied string in userspace.
The string is then copied to kernel space and the length returned to the
caller.
However userspace can modify the string at any time while the kernel
checks for the length of the string or copies the string. In result the
returned length of the string is not necessarily correct.
Fix this by copying in a loop which mimics the mvcos variant of
strncpy_from_user(), which handles this correctly.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-28 09:37:11 +01:00
Heiko Carstens
f45655f6a6 s390/uaccess: fix strncpy_from_user/strnlen_user zero maxlen case
If the maximum length specified for the to be accessed string for
strncpy_from_user() and strnlen_user() is zero the following incorrect
values would be returned or incorrect memory accesses would happen:

strnlen_user_std() and strnlen_user_pt() incorrectly return "1"
strncpy_from_user_pt() would incorrectly access "dst[maxlen - 1]"
strncpy_from_user_mvcos() would incorrectly return "-EFAULT"

Fix all these oddities by adding early checks.

Reviewed-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-28 09:37:08 +01:00
Heiko Carstens
d7b788cd06 s390/uaccess: shorten strncpy_from_user/strnlen_user
Always stay within page boundaries when copying from user within
strlen_user_mvcos()/strncpy_from_user_mvcos(). This allows to
shorten the code a bit and may prevent unnecessary faults, since
we copy quite large amounts of memory to kernel space.

Also directly call the mvcos variants of copy_from_user() to
avoid indirect branches.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-28 09:37:07 +01:00
Martin Schwidefsky
abf09bed3c s390/mm: implement software dirty bits
The s390 architecture is unique in respect to dirty page detection,
it uses the change bit in the per-page storage key to track page
modifications. All other architectures track dirty bits by means
of page table entries. This property of s390 has caused numerous
problems in the past, e.g. see git commit ef5d437f71
"mm: fix XFS oops due to dirty pages without buffers on s390".

To avoid future issues in regard to per-page dirty bits convert
s390 to a fault based software dirty bit detection mechanism. All
user page table entries which are marked as clean will be hardware
read-only, even if the pte is supposed to be writable. A write by
the user process will trigger a protection fault which will cause
the user pte to be marked as dirty and the hardware read-only bit
is removed.

With this change the dirty bit in the storage key is irrelevant
for Linux as a host, but the storage key is still required for
KVM guests. The effect is that page_test_and_clear_dirty and the
related code can be removed. The referenced bit in the storage
key is still used by the page_test_and_clear_young primitive to
provide page age information.

For page cache pages of mappings with mapping_cap_account_dirty
there will not be any change in behavior as the dirty bit tracking
already uses read-only ptes to control the amount of dirty pages.
Only for swap cache pages and pages of mappings without
mapping_cap_account_dirty there can be additional protection faults.
To avoid an excessive number of additional faults the mk_pte
primitive checks for PageDirty if the pgprot value allows for writes
and pre-dirties the pte. That avoids all additional faults for
tmpfs and shmem pages until these pages are added to the swap cache.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-14 15:55:23 +01:00
Heiko Carstens
1aae0560d1 s390/time: rename tod clock access functions
Fix name clash with some common code device drivers and add "tod"
to all tod clock access function names.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-02-14 15:55:10 +01:00
Gerald Schaefer
156152f84e s390/mm: use pmd_large() instead of pmd_huge()
Without CONFIG_HUGETLB_PAGE, pmd_huge() will always return 0. So
pmd_large() should be used instead in places where both transparent
huge pages and hugetlbfs pages can occur.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-10-26 16:44:23 +02:00
Heiko Carstens
535c611ddd s390/string: provide asm lib functions for memcpy and memcmp
Our memcpy and memcmp variants were implemented by calling the corresponding
gcc builtin variants.
However gcc is free to replace a call to __builtin_memcmp with a call to memcmp
which, when called, will result in an endless recursion within memcmp.
So let's provide asm variants and also fix the variants that are used for
uncompressing the kernel image.
In addition remove all other occurences of builtin function calls.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-09-26 15:44:50 +02:00
Gerald Schaefer
4db84d4f07 s390/mm: fix user access page-table walk code
The s390 page-table walk code, used for user copy and futex, currently
cannot handle huge pages. As far as user copy is concerned, that is
not really a problem because those functions will only be used on old
hardware that has no huge page support. But the futex code will also
use pagetable walk functions on current hardware when user space runs
in primary space mode. So, if a futex sits in a huge page, the futex
operation on it will result in a page fault loop or even data
corruption.

This patch adds the code for resolving huge page mappings in the user
access pagetable walk code on s390.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-09-17 09:44:24 +02:00
Martin Schwidefsky
27f6b41662 s390/vtimer: rework virtual timer interface
The current virtual timer interface is inherently per-cpu and hard to
use. The sole user of the interface is appldata which uses it to execute
a function after a specific amount of cputime has been used over all cpus.

Rework the virtual timer interface to hook into the cputime accounting.
This makes the interface independent from the CPU timer interrupts, and
makes the virtual timers global as opposed to per-cpu.
Overall the code is greatly simplified. The downside is that the accuracy
is not as good as the original implementation, but it is still good enough
for appldata.

Reviewed-by: Jan Glauber <jang@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-07-20 11:15:08 +02:00
Heiko Carstens
a53c8fab3f s390/comments: unify copyright messages and remove file names
Remove the file name from the comment at top of many files. In most
cases the file name was wrong anyway, so it's rather pointless.

Also unify the IBM copyright statement. We did have a lot of sightly
different statements and wanted to change them one after another
whenever a file gets touched. However that never happened. Instead
people start to take the old/"wrong" statements to use as a template
for new files.
So unify all of them in one go.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2012-07-20 11:15:04 +02:00
Heiko Carstens
f4815ac6c9 s390/headers: replace __s390x__ with CONFIG_64BIT where possible
Replace __s390x__ with CONFIG_64BIT in all places that are not exported
to userspace or guarded with #ifdef __KERNEL__.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-05-24 10:10:10 +02:00
Martin Schwidefsky
4c1051e37a [S390] rework idle code
Whenever the cpu loads an enabled wait PSW it will appear as idle to the
underlying host system. The code in default_idle calls vtime_stop_cpu
which does the necessary voodoo to get the cpu time accounting right.
The udelay code just loads an enabled wait PSW. To correct this rework
the vtime_stop_cpu/vtime_start_cpu logic and move the difficult parts
to entry[64].S, vtime_stop_cpu can now be called from anywhere and
vtime_start_cpu is gone. The correction of the cpu time during wakeup
from an enabled wait PSW is done with a critical section in entry[64].S.
As vtime_start_cpu is gone, s390_idle_check can be removed as well.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-03-11 11:59:28 -04:00
Martin Schwidefsky
8b646bd759 [S390] rework smp code
Define struct pcpu and merge some of the NR_CPUS arrays into it, including
__cpu_logical_map, current_set and smp_cpu_state. Split smp related
functions to those operating on physical cpus and the functions operating
on a logical cpu number. Make the functions for physical cpus use a
pointer to a struct pcpu. This hides the knowledge about cpu addresses in
smp.c, entry[64].S and swsusp_asm64.S, thus remove the sigp.h header.

The PSW restart mechanism is used to start secondary cpus, calling a
function on an online cpu, calling a function on the ipl cpu, and for
the nmi signal. Replace the different assembler functions with a
single function restart_int_handler. The new entry point calls a function
whose pointer is stored in the lowcore of the target cpu and it can wait
for the source cpu to stop. This covers all existing use cases.

Overall the code is now simpler and there are ~380 lines less code.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2012-03-11 11:59:28 -04:00
Martin Schwidefsky
3c52e49d7c [S390] sparse: fix sparse warnings with __user pointers
Use __force to quiet sparse warnings about user address space.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-10-30 15:16:46 +01:00
Martin Schwidefsky
b50511e41a [S390] cleanup psw related bits and pieces
Split out addressing mode bits from PSW_BASE_BITS, rename PSW_BASE_BITS
to PSW_MASK_BASE, get rid of psw_user32_bits, remove unused function
enabled_wait(), introduce PSW_MASK_USER, and drop PSW_MASK_MERGE macros.
Change psw_kernel_bits / psw_user_bits to contain only the bits that
are always set in the respective mode.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-10-30 15:16:43 +01:00
Jan Glauber
144d634a21 [S390] fix s390 assembler code alignments
The alignment is missing for various global symbols in s390 assembly code.
With a recent gcc and an instruction like stgrl this can lead to a
specification exception if the instruction uses such a mis-aligned address.

Specify the alignment explicitely and while add it define __ALIGN for s390
and use the ENTRY define to save some lines of code.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 10:48:21 +02:00
Heiko Carstens
b396637841 [S390] delay: implement ndelay
Implement ndelay() on s390 as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-05-26 09:48:25 +02:00
Michel Lespinasse
8d7718aa08 futex: Sanitize futex ops argument types
Change futex_atomic_op_inuser and futex_atomic_cmpxchg_inatomic
prototypes to use u32 types for the futex as this is the data type the
futex core code uses all over the place.

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311025058.GD26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-11 12:23:31 +01:00
Michel Lespinasse
37a9d912b2 futex: Sanitize cmpxchg_futex_value_locked API
The cmpxchg_futex_value_locked API was funny in that it returned either
the original, user-exposed futex value OR an error code such as -EFAULT.
This was confusing at best, and could be a source of livelocks in places
that retry the cmpxchg_futex_value_locked after trying to fix the issue
by running fault_in_user_writeable().
    
This change makes the cmpxchg_futex_value_locked API more similar to the
get_futex_value_locked one, returning an error code and updating the
original value through a reference argument.
    
Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>  [tile]
Acked-by: Tony Luck <tony.luck@intel.com>  [ia64]
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michal Simek <monstr@monstr.eu>  [microblaze]
Acked-by: David Howells <dhowells@redhat.com> [frv]
Cc: Darren Hart <darren@dvhart.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110311024851.GC26122@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-03-11 12:23:08 +01:00
Martin Schwidefsky
e4d82692f4 [S390] missing sacf in uaccess
The uaccess functions copy_in_user_std and clear_user_std fail to
switch back from secondary space mode to primary space mode with sacf
in case of an unresolvable page fault. We need to make sure that the
switch back to primary mode is done in all cases, otherwise the code
following the uaccess inline assembly will crash.

Reported-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-01-31 11:30:20 +01:00
Heiko Carstens
545b288dcb [S390] time: let local_tick_enable/disable() reprogram the clock comparator
Let local_tick_enable/disable() reprogram the clock comparator so the
function names make semantically more sense.
Also that way the functions are more symmetric since normally each
local_tick_enable() call usually would have a subsequent call to
set_clock_comparator() anyway.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-01-05 12:47:25 +01:00
Heiko Carstens
e8129c6421 [S390] nmi: fix clock comparator revalidation
On each machine check all registers are revalidated. The save area for
the clock comparator however only contains the upper most seven bytes
of the former contents, if valid.
Therefore the machine check handler uses a store clock instruction to
get the current time and writes that to the clock comparator register
which in turn will generate an immediate timer interrupt.
However within the lowcore the expected time of the next timer
interrupt is stored. If the interrupt happens before that time the
handler won't be called. In turn the clock comparator won't be
reprogrammed and therefore the interrupt condition stays pending which
causes an interrupt loop until the expected time is reached.

On NOHZ machines this can result in unresponsive machines since the
time of the next expected interrupted can be a couple of days in the
future.

To fix this just revalidate the clock comparator register with the
expected value.
In addition the special handling for udelay must be changed as well.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-11-25 09:52:59 +01:00
Heiko Carstens
596a95cdf0 [S390] uaccess: make sure copy_from_user_overflow is builtin
If there is no in kernel image caller modules will suffer:

ERROR: "copy_from_user_overflow" [net/core/pktgen.ko] undefined!
ERROR: "copy_from_user_overflow" [net/can/can-raw.ko] undefined!
ERROR: "copy_from_user_overflow" [fs/cifs/cifs.ko] undefined!

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-03-08 12:25:29 +01:00
Gerald Schaefer
59b6978745 [S390] spinlock: check virtual cpu running status
This patch introduces a new function that checks the running status
of a cpu in a hypervisor. This status is not virtualized, so the check
is only correct if running in an LPAR. On acquiring a spinlock, if the
cpu holding the lock is scheduled by the hypervisor, we do a busy wait
on the lock. If it is not scheduled, we yield over to that cpu.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26 22:37:31 +01:00
Heiko Carstens
1dcec254af [S390] uaccess: implement strict user copy checks
Same as on x86 and sparc, besides the fact that enabling the option
will just emit compile time warnings instead of errors.
Keeps allyesconfig kernels compiling.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26 22:37:29 +01:00
Heiko Carstens
fb380aadfe [S390] Move __cpu_logical_map to smp.c
Finally move it to the place where it belongs to and make get rid of
it for !CONFIG_SMP.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-01-13 20:44:45 +01:00
Thomas Gleixner
e5931943d0 locking: Convert raw_rwlock functions to arch_rwlock
Name space cleanup for rwlock functions. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
2009-12-14 23:55:32 +01:00
Thomas Gleixner
fb3a6bbc91 locking: Convert raw_rwlock to arch_rwlock
Not strictly necessary for -rt as -rt does not have non sleeping
rwlocks, but it's odd to not have a consistent naming convention.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
2009-12-14 23:55:32 +01:00
Thomas Gleixner
0199c4e68d locking: Convert __raw_spin* functions to arch_spin*
Name space cleanup. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
2009-12-14 23:55:32 +01:00
Thomas Gleixner
445c89514b locking: Convert raw_spinlock to arch_spinlock
The raw_spin* namespace was taken by lockdep for the architecture
specific implementations. raw_spin_* would be the ideal name space for
the spinlocks which are not converted to sleeping locks in preempt-rt.

Linus suggested to convert the raw_ to arch_ locks and cleanup the
name space instead of using an artifical name like core_spin,
atomic_spin or whatever

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: linux-arch@vger.kernel.org
2009-12-14 23:55:32 +01:00
Gerald Schaefer
6c1e3e7943 [S390] Use do_exception() in pagetable walk usercopy functions.
The pagetable walk usercopy functions have used a modified copy of the
do_exception() function for fault handling. This lead to inconsistencies
with recent changes to do_exception(), e.g. performance counters. This
patch changes the pagetable walk usercopy code to call do_exception()
directly, eliminating the redundancy. A new parameter is added to
do_exception() to specify the fault address.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:34 +01:00
Martin Schwidefsky
b11b533427 [S390] Improve address space mode selection.
Introduce user_mode to replace the two variables switch_amode and
s390_noexec. There are three valid combinations of the old values:
  1) switch_amode == 0 && s390_noexec == 0
  2) switch_amode == 1 && s390_noexec == 0
  3) switch_amode == 1 && s390_noexec == 1
They get replaced by
  1) user_mode == HOME_SPACE_MODE
  2) user_mode == PRIMARY_SPACE_MODE
  3) user_mode == SECONDARY_SPACE_MODE
The new kernel parameter user_mode=[primary,secondary,home] lets
you choose the address space mode the user space processes should
use. In addition the CONFIG_S390_SWITCH_AMODE config option
is removed.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07 12:51:33 +01:00
Gerald Schaefer
af9d2ff9af [S390] Add EX_TABLE for addressing exception in usercopy functions.
This patch adds an EX_TABLE entry to mvc{p|s|os} usercopy functions that
may be called with KERNEL_DS. In combination with collaborative memory
management, kernel pages marked as unused may trigger an adressing exception
in the usercopy functions. This fixes an unhandled addressing exception bug
where strncpy_from_user() is used with len > strnlen and KERNEL_DS, crossing
a page boundary to an unused page.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06 10:35:10 +02:00
Heiko Carstens
0cd6a403e8 [S390] Provide arch specific mdelay implementation.
Use an own implementation instead of the common code udelay loop.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06 10:35:08 +02:00
Christian Borntraeger
78d81f2f84 [S390] Fix enabled udelay for short delays.
When udelay() gets called with a delay that would expire before the
next clock event it reprograms the clock comparator.
When the interrupt happens the clock comparator won't be resetted
therefore the interrupt condition doesn't get cleared.
The result is an endless timer interrupt loop until the next clock
event would expire (stored in lowcore).
So udelay() usually would wait much longer for small delays than it
should.

Fix this by disabling the local tick which makes sure that the clock
comparator will be resetted when a timer interrupt happens.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06 10:35:08 +02:00
Heiko Carstens
5075baca2e [S390] add __ucmpdi2() helper function
Provide __ucmpdi2() helper function on 31 bit so we don't run
again and again in compile errors like this one:

kernel/built-in.o: In function `T.689':
perf_counter.c:(.text+0x56c86): undefined reference to `__ucmpdi2'

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-07-07 16:37:53 +02:00
Heiko Carstens
bb8c29caff [S390] udelay: disable lockdep to avoid false positives
Our udelay implementation enables interrupts to receive a special timer
interrupt regardless of the context it is called from.
This might lead to false positive lockdep reports. Since lockdep isn't
aware of the fact that only a single interrupt source is enabled it
warns about possible deadlocks that in reality won't happen, like
the one below.
To fix this disable lockdep before enabling interrupts.

[ 254.040888] =================================
[ 254.040904] [ INFO: inconsistent lock state ]
[ 254.040910] 2.6.30 #9
[ 254.040914] ---------------------------------
[ 254.040920] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[ 254.040927] swapper/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
[ 254.040934] (sch->lock){?.-...}, at: [<00000000002e4778>] ccw_device_timeout+0x48/0x2f0
[ 254.040961] {IN-HARDIRQ-W} state was registered at:
[ 254.040969] [<0000000000096f74>] __lock_acquire+0x9d4/0x188c
[ 254.040985] [<0000000000097f68>] lock_acquire+0x13c/0x16c
[ 254.040998] [<00000000004527e0>] _spin_lock+0x74/0xb8
[ 254.041016] [<0000000000457eb2>] do_IRQ+0xde/0x208
[ 254.041031] [<000000000002d190>] io_return+0x0/0x8
[ 254.041049] [<0000000000029faa>] vtime_stop_cpu+0xbe/0x114
[ 254.041066] irq event stamp: 259629
[ 254.041076] hardirqs last enabled at (259628): [<000000000045238e>] _spin_unlock_irq+0x5e/0x9c
[ 254.041095] hardirqs last disabled at (259629): [<000000000045292e>] _spin_lock_irq+0x4a/0xc4
[ 254.041126] softirqs last enabled at (259614): [<000000000006500e>] __do_softirq+0x296/0x2b0
[ 254.041137] softirqs last disabled at (259619): [<0000000000024cf6>] do_softirq+0x102/0x108
[ 254.041147]
[ 254.041148] other info that might help us debug this:
[ 254.041153] 2 locks held by swapper/0:
[ 254.041157] #0: (&priv->timer){+.-...}, at: [<000000000006bf9a>] run_timer_softirq+0x19a/0x340
[ 254.041170] #1: (sch->lock){?.-...}, at: [<00000000002e4778>] ccw_device_timeout+0x48/0x2f0
[ 254.041182]
[ 254.041310] Call Trace:
[ 254.041313] ([<00000000000174fc>] show_trace+0x16c/0x170)
[ 254.041321] [<0000000000017578>] show_stack+0x78/0x104
[ 254.041327] [<000000000044d0ca>] dump_stack+0xc6/0xd4
[ 254.041342] [<00000000000949b4>] print_usage_bug+0x1c8/0x1fc
[ 254.041353] [<0000000000094e8a>] mark_lock+0x4a2/0x670
[ 254.041364] [<00000000000950e2>] mark_held_locks+0x8a/0xb4
[ 254.041375] [<0000000000095398>] trace_hardirqs_on_caller+0x74/0x1ac
[ 254.041388] [<00000000000954fa>] trace_hardirqs_on+0x2a/0x38
[ 254.041402] [<000000000025f1ec>] __udelay_disabled+0xac/0xfc
[ 254.041419] [<000000000025f432>] __udelay+0x12a/0x148
[ 254.041433] [<00000000002d64d8>] cio_commit_config+0x170/0x290
[ 254.041451] [<00000000002d6978>] cio_disable_subchannel+0x120/0x1cc
[ 254.041468] [<00000000002e32a4>] ccw_device_recog_done+0x54/0x2f4
[ 254.041485] [<00000000002e3638>] ccw_device_sense_id_done+0x50/0x90
[ 254.041508] [<00000000002e615a>] snsid_callback+0xfa/0x3a8
[ 254.041515] [<00000000002dd96c>] ccwreq_stop+0x80/0x90
[ 254.041523] [<00000000002dda8e>] ccw_request_timeout+0xc2/0xd0
[ 254.041530] [<00000000002e2f70>] ccw_device_request_event+0x58/0x90
[ 254.041537] [<00000000002e47ae>] ccw_device_timeout+0x7e/0x2f0
[ 254.041555] [<000000000006c02a>] run_timer_softirq+0x22a/0x340
[ 254.041566] [<0000000000064eb0>] __do_softirq+0x138/0x2b0
[ 254.041578] [<0000000000024cf6>] do_softirq+0x102/0x108
[ 254.041590] [<00000000000647ce>] irq_exit+0xee/0x114
[ 254.041603] [<0000000000457d88>] do_extint+0x130/0x17c
[ 254.041617] [<000000000002d41e>] ext_no_vtime+0x1e/0x22
[ 254.041631] [<0000000000029faa>] vtime_stop_cpu+0xbe/0x114
[ 254.041646] ([<0000000000029f58>] vtime_stop_cpu+0x6c/0x114)
[ 254.041662] [<000000000001d842>] cpu_idle+0x122/0x1c0
[ 254.041679] [<00000000004482c6>] start_secondary+0xce/0xe0
[ 254.041696] [<0000000000000000>] 0x0
[ 254.041715] [<0000000000000000>] 0x0
[ 254.041745] INFO: lockdep is turned off.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-07-07 16:37:51 +02:00
Linus Torvalds
d06063cc22 Move FAULT_FLAG_xyz into handle_mm_fault() callers
This allows the callers to now pass down the full set of FAULT_FLAG_xyz
flags to handle_mm_fault().  All callers have been (mechanically)
converted to the new calling convention, there's almost certainly room
for architectures to clean up their code and then add FAULT_FLAG_RETRY
when that support is added.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-21 13:08:22 -07:00
Heiko Carstens
ce58ae6f7f [S390] implement interrupt-enabling rwlocks
arch backend for f5f7eac41d
"Allow rwlocks to re-enable interrupts".

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 10:27:29 +02:00
Heiko Carstens
1edad85b16 [S390] use compiler builtin versions of strlen/strcpy/strcat
Use builtin variants if gcc 4 or newer is used to compile the kernel.
Generates better code than the asm variants.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:24 +01:00
Heiko Carstens
1485c5c884 [S390] move EXPORT_SYMBOLs to definitions
Move all EXPORT_SYMBOLs to their corresponding definitions.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-26 15:24:11 +01:00
Gerald Schaefer
2887fc5aa6 [S390] Dont check for pfn_valid() in uaccess_pt.c
pfn_valid() actually checks for a valid struct page and not for a
valid pfn. Using xip mappings w/o struct pages, this will result in
-EFAULT returned by the (page table walk) user copy functions,
even though there is valid memory. Those user copy functions don't
need a struct page, so this patch just removes the pfn_valid() check.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:13 +01:00
Martin Schwidefsky
4fa81ed277 [S390] __div64_31 broken for CONFIG_MARCH_G5
The implementation of __div64_31 for G5 machines is broken. The comments
in __div64_31 are correct, only the code does not do what the comments
say. The part "If the remainder has overflown subtract base and increase
the quotient" is only partially realized, the base is subtracted correctly
but the quotient is only increased if the dividend had the last bit set.
Using the correct instruction fixes the problem.

Cc: stable@kernel.org
Reported-by: Frans Pop <elendil@planet.nl>
Tested-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 13:28:12 +01:00
Heiko Carstens
5a0d0e6537 [S390] Move private simple udelay function to arch/s390/lib/delay.c.
Move cio's private simple udelay function to lib/delay.c and turn it
into something much more readable. So we have all implementations
at one place.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-10 21:33:58 +02:00
Heiko Carstens
d3d238c774 [S390] nohz: Fix __udelay.
This fixes a regression that came with 934b2857cc
("[S390] nohz/sclp: disable timer on synchronous waits.").
If udelay() gets called from a disabled context it sets the clock comparator
to a value where it expects the next interrupt. When the interrupt happens
the clock comparator gets not reset and therefore the interrupt condition
doesn't get cleared. The result is an endless timer interrupt loop.

In addition this patch fixes also the following:

rcutorture reveals that our __udelay implementation is still buggy,
since it might schedule tasklets, but prevents their execution:

NOHZ: local_softirq_pending 42
NOHZ: local_softirq_pending 02
NOHZ: local_softirq_pending 142
NOHZ: local_softirq_pending 02

To fix this we make sure that only the clock comparator interrupt
is enabled when the enabled wait psw is loaded.
Also no code gets called anymore which might schedule tasklets.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-10-03 21:55:54 +02:00